Helena

 Helena is a friend of Hermia and she tried to win the love of Demetrius, but Demetrius hated her and he loved Hermia instead. This caused Helena to have jealousy against Hermia. Just like her, she too is very persistent about her wills (like making Demetrius love her). This can be understood from her telling where Hermia is just to win the love of Demetrius.